Printing plate cylinder



April 29, 1958 c. A. HARLI-:ss 2,832,283

' PRINTING PLATE CYLINDER Filed Jan. 2o, 195e 4 sheets-sheet 1 WMM\ am .MM.MM Minn wwmm .mI

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4,5% vBY .9g I i April 29, 1958 c. A. HARLEss PRINTING PLATE CYLINDER 4 Shets-Sheet 2 Filed Jan. 20, 1956 FIG. 4.

INVENTOR z April 29, 1958l c. A. HARLEss PRINTING PLATE CYLINDER Filed Jan. 20, 1956 4 Sheets-Sheet 5 A; IORNEYS' April 29 1958 c. A. HARLr-:ss

PRINTING PLATE CYLINDER 4 Sheets-Sheet 4 Filed Jan. 20, 1956 A ORNEY5 o iitent Patented Apr. 29, 1958 par Piiil'sllllbl PLATE CYLENDER Charles A.. Hariess, Riverside, Conn., assigner to R. Hoe da Co., Inc., New Yorlt, N, Y., a 'corporation of New Vorif a i Application .lanuaryzlh 1956, Serial No. 560,342

3 (Ci. lill-37d) This invention relates to printing machine plate cylinders, and, more particularly, to plate clamping mechanism for attaching stereotype or similar printing plates to such cylinders.

The invention is concerned with cylinders of the type in which the plates are held by clips or hooks engaging underneath the plates for holding them on the cylinder. Prior Harless Patent 2,708,875 shows a cylinder of this type, which is adjustable for plates of different widths by providing a number of plate clamping assemblies or units together with means for shifting them axially of the cylinder, andthe present invention is, in one aspect, an improvement upon the disclosure of that patent, being concerned with improvements in the individual clamping assemblies or units and also in the operating mechanism therefor. Prior copending Harless application Serial No. 336,236, led February il, 1953, for Printing Plate Cylinder also discloses a cylinder of this type and the present application is a continuation in part or improvement thereon.

One object of the invention is to provide ra plate clamping mechanism which requires minimum exertion in locking up the plates or moving the hooks into plate holding position, while, at the same time, the major part of the movement to and from clamping position may be very rapid.

A second object is to provide plate clamping units which will exert even clamping pressure on a plurality of hooks despite irregularities in the cooperating plate recesses or deliberate cooking of the plates for obtaining color registi-y.

Another object is to provide plate clamping mechanism of an exceptionally rugged character in which wear is reduced to a minimum and the eects of such wear as may occur are also minimized.

With the foregoing objects in mind, as well as still other objects which wiil appear .in the course of the description, 'a mechanism embodying the invention in a preferred form will now first be described with reference to the accompanying drawing and the features forming the invention will then be pointed out in the appended claims.

ln the drawing:

Fig. l is a largely schematic plan View of a printing plate cylinder embodying the invention in a preferred form;

Fig. 2 is a fragmentary view similar to Fig. l, but showing only one end of the cylinder and showing the same arranged for plates of a different width;

Fig. 3 is an enlarged fragmentary end elevation of the cylinder, showing operating mechanism for the plate clamping mechanism;

Fig. 4 is m enlarged ragmentary plan View showing part of the mechanism of Fig. l and with parts removed to show the internal construction more clearly;

Figs. d-A-i-i, inclusive, are detail views showing various parts forming a plate clamping assembly in Fig. 4;

Fig. 5 is a rather enlarged plan View showing a single plate clamping assembly in plan view and with parts 2 broken away to show the construction more clearly.; .and

Figs. 6 and 7 are, respectively, sections on the lines 6-6 and 7--7 of Fig. 5, and respectively show the parts in plate clamping and plate releasing position.

The structure of the cylinder in general is similar to that of prior Harless Patent 2,708,875 and application Serial No. 336,236, filed February 11, 1953 for Improvements in Printing Plate Cylinder, in .that it utilizes a number of plate clamping units or assemblies `indicated .genen ally by the numeral lil, together with spacer blocks l1 which fit in grooves l2 in the plate cylinder. As .in the structure of the said patent and application, the cylinder has a bore t3 within which there is rotatably carried a continuous cam shaft 14 by turning which the various plate clamping mechanisms are operated. As `shown in Fig. 3 there is fixed to the end of thisshaft ld and arm l pivotally connected to a link 16 which in turn is pivotally connected to a crank arm ll carried on a stub shaft 13 and having a socket `19 for receiving a wrench 20. The full line position of the parts in Fig. 3 is vthe plate locking position and the phantom position shows the same Vin released position. it will be noted that in the plate locking position, the pivot centers are aligned so that there is no torque exerted upon the crank. The end 21 which receives the wrench 2t) may also be made suiciently heavy by comparison with the crank arm and link 16 so that centrifugal force will tend to urge the parts toward lock up position. A stop 22 cooperating with an adjustable screw threaded element V2213 serves to limit movement of the parts in the plate clamping directionand a spring .de- -tent 24 cooperating with a recess 25 under the crank end 2l may be provided for holding the elements in unclemping position. In Fig. 2 the parts are shown as associated with spacer blocks ll', which are larger than the blocks ll of Fig. l, and it will be observed that the plates indicated in phantom are wired. As in the above `mentioned patent, provision is thus made for accommodating with the same mechanism and by very simple adjustments plates of various sizes. The mechanisms shown are, as will be understood, normally reduplicated at t'heopposite side of the cylinder, so that the cylinder shown 'is adapted to taking two plates around and `four plates across, or a total of eight plates in all. As will be apparent, however, the `invention is not restricted to a cylinder of this type but the plate clamping mechanism may be used with cylinders having practically any desired number of plates around or plates across the cylinder.

As will appear from the following description, the various parts of a plate clamping assembly or unit l@ are, by comparison with prior structures, of a very massive character, while the unit itself is very compact. This result is achieved by a shaping and `intertting of parts for utilizing the available space to best advantage, making structure somewhat diilicult to showin a drawing. For this reason, a number of different views have been p1'o vided, which will now be described rather fully,.for convenience of reference:

Fig. 4 shows a pair of clamping units 10, in place in the cylinder, and slightly separated, but with spacer block omitted to show the bottom of the cylinder-groove. In the right hand clamping unit 10, a block member 3i), shown on the left hand clamping unit has been removed, to show the parts it carries, in their operating position.

Fig. 4-C is a bottom plan view of the block member 30 removed from the right hand unit 10 of Fig. 4 and is shown projected directly beneath this member in Fig. 4.

The remaining figures, 1f-A, 4-B and l-D-ll-K, are perspectives and elevational views on convenient scales `and are intended to supplement the other views by clarifying the shape of the various elements.

Fig. 5 Visa plan `vit=.w,generally similar to the right 3 hand part of Fig. 4, but further enlarged and broken away, as later described in detal, to further clarify the construction. The block member 30 is there shown in phantom.

Fig. 6 is a section on line 6-6 of Fig. 5, showing the parts in the same position, which is the plate clamping position, as in that figure, and showing the block member 30 in solid lines.

Fig. 7 is a similar section on line 7 7 of Fig. 5, but showing the parts in plate releasing position, and is projected directly beneath Fig. 6 to aid in locating the parts and following their movement.

As appears most clearly from Figs. 6 and 7, the cam shaft bore 13 overlaps the generally rectangular cylinder groove 12 to the extent of about 90 of the bore 13, so that the center of `bore 13 is located just about at the intersection of a `continuation of the floor and side wall of groove 12. This leaves about 279 of support for cam shaft 14 by the wall of bore 13 and exposes about 90 of the cam shaft for operating the clamping units 1d.

The block member 30 has a configuration, when viewed from the top, which is substantially rectangular (left side of Fig. 4) and an upper surface which continues the sur- `face of the cylinder generally (Figs. 6 and 7). Openings 31 are provided for spring pressed hooks 32 as `well `as openings 33 for rigid hooks 34. Edge surfaces 35 of block 30 sit on a ledge or shoulder 36 at one side of groove 12 (Figs. 4 to 7) and edge surfaces 37 sit on a ledge or shoulder 33 at the other side of the groove 12. Block 30 is held down in the groove 12 by means of screws 40 having their heads countersunk in the block 30, and their screw threaded ends are received in bores 41 and dovetail bars 42 (Figs. 4, 4-1 and 6) which lit slidably in `dovetail groove 43 at the bottom of cylinder groove 12. As in the previous Harless patent, abovementioned, this permits locating the units anywhere `along the groove 12. The Iblock 30, except where cut away to accommodate the parts, as later described, lits and fills the groove 12.

The rigid hooks 34 are formed on bell crank members 50 (see Fig. 4D for shape), the hubs 51 of which have bores 52 receiving a shaft 53 (Figs. 4-7) which is fitted in bores 54 in downwardly projecting parts 55 (Figs. 4, 6, 7) of the block 30. Bores 56 in the other arms of the bell crank members 50 receive crowned or rounded trunnions 57 (Fig. 5 and 6) at the end of a bar 58 (Fig. 4E) which bar has a central bore 59 receiving a threaded stud 60 xed to a dovetail shaped hea-d 61 (Fig. 4 1) fitting the dovetail groove 43 (Fig. 7). The upper part of bar 58 around bore 59 is formed as a spherical seat 62 receiving the correspondingly spherical head 63 of a nut 64 (Figs. 7 and 4-K) which lits the threaded top of stud 60. A hexagon recess 65 in nut 64 takes the usual Allen wrench for turning the nut 64, and thereby depressing bar 58 to any desired extent. Springs 66 are provided in bores 67 in dovetail bars 42 (Fig. 4-J and 6) for engaging bell cranks 5t) to urge bar 58 upward against nut 64. Since trunnions 57 are crowned and the seat 62 is spherical, the bar 58 may tilt or rock, advancing one hook 34 and moving back the other, circumferentially of the cylinder. A point midway between the two hooks 34 will, however, be accurately xed, so that the mechanism permits accurate registry while taking plates with misaligned hook receiving pockets or while taking plates in cocked position on the cylinder. The rim of nut 64 is notched as at 68 (Figs. 4-K, 5 and 7) and a spring pressed detent 69 engages in the notches for holding the nut 64 in adjusted position. The turning of nut 64 from notch to notch past Y the detent 69 makes an audible click, so that by counting these `clicks the pressman is able to advance or move back a pair of hooks 34 through an accurately determined distance.

The hooks 32 are operated 'by a mechanism generally similar to that of the above-mentioned Harless applicatheroller.

'4 tion, but improved in many respects. A shaft 70 xed in bores 71 in downward projections 72y o-f the block member 30 (Fig. 4C) carries hooks 32 (shown in perspective in Fig. 4-1) and also operating arms 73 (shown in perspective in Fig. 4-A). A preloaded spring frame 74 (Fig. 5) serves as a connecting member for `applying `clamping pressure.

A pair (right and left hand) of arms 73 are positioned on shaft 70 with their hubs 75 against each other (Fig. 5) and carry between their heads 76 a roller 77 which has crowned or barreled trunnions 78 received in bores 79 in the arm heads 76. This roller follows the cam shaft 14, as later described. The hubs 80 of hooks 32 (also right and left hand) are likewise `carried on shaft 70 outside the hubs 75 of the arms 73 so the hubs 75 and Str till the space between frame projections 72, apart from operating clearances. Each hook 32 has a crowned or barreled stub shaft or trunnion 81 received in a bore 82 in the spring frame 74 (Fig. 5), and coupling the hook to the spring frame for application of clamping pressure.

Spring frame 74 surrounds the nut 64, previously mentioned (Fig. 5) and contains a pair of poppet rods 83 (Fig. 4-H). Spring frame 74 is substantially rectangular. Figs. 4F and 4-G are, respectively, an end elevation and side elevation of this element, shown as removed from the mechanism, and serve, in conjunction with the other views, to complete the showing as to the shape of this element. The enlarged heads 84 of rods 83 are cylindrical and t slidably in bores 85 in the spring frame 74. Springs 86 thrust against heads 34 through washers 87, the other ends of springs 86 reacting against the frame 74, as shown. At their opposite ends, the rods 83 are reduced and are slidably received in bushings 88. As viewed in -a plane at right `angles to the cylinder axis the heads of rods 83 have the configuration shown in Figs. 4II and 7, being cylindrical about the axis of bores 82 when the parts are in fully clamped position. Heads 76 of the operating arms engage the heads 84, having at 89 (Figs. 4-A and 7) correspondingly cylindrical but concave surfaces Afor engaging the heads 84. Frame 74 carries a projection 90 (Figs. 4 7) for dislodging a plate while unlocking the same.

The cam shaft 14 has a recess 91 (Fig. 6) which receives roller 77 (Fig. 7) in unclamping position and has a rise 92 for forcing the roller from the unclamped position of Fig. 7 to the clamping position of Fig. 6. A substantial high dwell 93 is provided, and may occupy about 20, as shown. A recess 94 receives a projection or toe 95 in each of the hooks 32, abutment 96 at one side of the recess serving to engage the toe 95 for retracting the parts from clamped position.

In operation, and starting from the unclamped position of Fig. 7, cam shaft 14 is rotated counter-clockwise,

, forcing roller 77 from the position of Fig. 7 to that of Fig. 6, and correspondingly pivoting arms 73 which carry During most of this movement, rods 84, frame 74 and hook arms 32 move as a unit, the end 97 of the frame '74 sliding in the space between ledge 36 and surface 95d of the block 3i). Since springs 86 are not compressed during most of this movement, but little force is required to turn the 4cam 14. Toward the end of the clamping movement, hooks 32 will engage in the plate recesses, substantially stopping further movement of these hooks and also of frame 74 attached to them by stub shafts 81. Thereafter, further rotation of the cam 14 will push poppet rods 83 into frame 74, compressing springs 86. Springs 36 are preferably long so that the precise amount of unseating of the poppet rods 83 does not greatly change the clamping pressure applied, this pressure remaining close to the preload value, in any case. Once the roller 77 is on the high dwell 93, the clamping force exerted by the hook 32 exerts no torque against cam shaft 14. In unclamping, or moving from the position of Fig. 6 to that of Fig. 7 the initial movement of cam shaft 14 permits springs 86 to expand to their limit. Thereafter, when abutment 96 engages toe 9S further rotation of cam shaft 1d turns the hook arms 32 from the position of Fig. 6 to that of Fig. 7. The frame 74 being coupled to the arms 32 will follow and in so doing will push the operating arms 73, so that all parts move to the position of Fig. 7.

The recesses 9.?. and 94 are preferably slightly tapered in form, so that the rollers 77 move in sequence, instead of simultaneously, as they approach the final clamping position. Once a roller 77 is on the high dwell d3, it does not further resist turning of the cam shaft 14, so that this sequential operation cuts the force required to turn the shaft 1d in locking up to a fraction of what would otherwise be needed. Roller 77 can accommodate to a slightly tapered cam by reason of its crowned trunnions 7S and the mounting of its carrying arms 73 for independent turning on the shaft 70. Similarly, the rods 83 may cornpress independently and frame 74 may swing slightly, permitting one hook 32 to engage fully slightly ahead of the other.

What is claimed is:

1. In a printing machine plate cylinder, a plurality of plate clamping mechanisms arranged in axial alignment along the cylinder, each plate clamping mechanism including a cam follower for actuating it, operating mecha nism therefor comprising a continuous cam shaft having a cylindrical high dwell for engaging the said cam followers in axially aligned position, and a rise for forcing the said followers radially outward from the center of the cam shaft upon rotation thereof so as to bring them on the high dwell, the said rise having a slightly tapered configuration, whereby a plurality of followers engaging the said cam shaft will be successively forced onto the high dwell thereof upon rotary movement of the said cam shaft.

2. A printing machine plate cylinder comprising a plurality of plate clamping mechanisms arranged in axial alignment along the cylinder, each plate clamping mechanism including a cam follower roller for actuating it, operating mechanism therefor comprising a continuous cam shaft having a cylindrical high dwell for engaging the said cam follower rollers in axially aligned position, and a rise for forcing the said rollers radially outward from the center of the cam shaft upon rotation thereof so as to bring them on the high dwell, the said rise having a slightly tapered configuration, whereby a plurality of follower rollers engaging the said cam shaft will be successively forced onto the high dwell thereof upon rotary movement of the said cam shaft.

3. A printing machine plate cylinder according to claim 2, comprising means mounting the said cam follower rollers for tilting movement with respect to the cam shaft, whereby the cam follower rollers are enabled to engage substantially normal to both the surface of the tapered rise and the surface of the cylindrical high dwell.

4. A printing machine plate cylinder according to claim 3, in which the said means mounting a cam follower roller comprises a pair of arms supporting the roller and means pivotally mounting the arms for independent rotary movement.

5. A printing machine plate cylinder according to claim 4, in which the follower roller is mounted in the pair of arms by means of self-aligning bearings.

6. A printing machine plate cylinder according to claim 5, in which the self-aligning bearings comprise trunnions having convex curvation in planes through the roller axis.

7. In a printing cylinder plate clamping mechanism comprising an operating arm, a pair of hooks for entering in recesses under a plate and clamping it to a cylinder, a pair of operating arms, a shaft rotatably supporting the said hooks and operating arms for independent pivotal movement, a roller carried by the two said operating arms for engaging the said operating cam, and spring means connecting the operating arms and hooks, whereby the said roller is capacitated to engage a cam. surface slanted with reference to the axis of the said shaft and also to engage a cam surface parallel thereto, and the hooks are capacitated for engaging in recesses in alignment with the said shaft and also in recesses out of alignment therewith.

8. In a printing cylinder plate clamping mechanism, a hook for engaging in a recess under a plate to clamp the same to a cylinder, means pivotally mounting the hook, an operating arm and means for pivotally mounting the operating arm coaxial with the hook, a spring assembly connecting the operating arm and hook for moving the latter and comprising a frame, means pivotally connecting one end of the frame to the hook, a spring poppet rod slidably carried by the frame and having a head engaging the operating arm, the said head being curved in a plane at right angles to the pivotal axis about a point substantially coaxial with the pivotal connection between frame and hook when the spring poppet rod is pushed into its limit, whereby at intermediate compression, the force exerted by the said poppet rod exerts a turning moment on the frame in a constant direction about the said pivotal axis.

References Cited in the file of this patent UNITED STATES PATENTS 905,162 Evensen Dec. 1, 1908 1,128,853 Cooper Feb. 16, 1915 2,639,668 Chase et al. May 26, 1953 2,667,834 Ziebell Feb. 2, 1954 2,708,875 Harless May 24, 1955 

